Solubilities of the compounds, $Ca(OH{)}_2$ and NaCl, at different temperatures are given below:

$\backslash$table$[[\frac{\frac{t}{}C}{60},\frac{Ca(OH{)}_2}{\text{N}\text{a}\text{C}\text{l}},],[80,0\mathrm{.}083,37\mathrm{.}05],[80,0\mathrm{.}066,38\mathrm{.}05]]$

$($a$)$ Calculate the heat of solution for the two systems.

$($b$)$ Interpret the calculated values of the heat of the solutions.

$]=-11\mathrm{.}2\frac{kJ}{m}ol,H_{\text{s}\text{o}\text{l}\text{u}\text{t}\text{i}\text{o}\text{n}}(NaCl)=[1\mathrm{.}30\frac{kJ}{m}ol$

$98$